SETI’s Colossus

by Paul Gilster on May 31, 2013

For the most part, the focus of SETI since Project Ozma has been directed at intercepting signals deliberately sent our way. It doesn’t have to be so, of course, because extraneous signals from a civilization going about its business would also be profoundly interesting, and even a civilization not much more advanced than ours might be throwing off powerful evidence of its existence through the planetary radars it uses to detect potential impactors in its own system.

Whether or not the Ohio State WOW! signal was a SETI detection remains unresolved, but I always think back to the original Cocconi and Morrison paper “Searching for Interstellar Communications,” published in Nature in 1959. Neither man could know in that year whether exoplanets even existed, but it was a reasonable supposition, and technology had advanced to the point where detecting SETI signals was consistent with all we knew. And as the duo wrote: “The probability of success is difficult to estimate, but if we never search, the chance of success is zero.”

Again I’m reminded of Freeman Dyson’s dictum ‘look for what’s detectable, not for what’s probable,’ which reminds us not to bring too many assumptions into the mix. Thus today we’re seeing the growth of interest in interstellar artifacts, perhaps in the form of gigantic engineering projects that would be observable across light years. And now we have a new proposal, one that would use a gigantic telescope housed here on Earth to look for infrared signatures around other stars. These would not be beacons but the infrared excess inevitably generated by a civilization going about its business. We needn’t, in other words, wait for them to send to us.

The Largest of All Telescopes

Four researchers have outlined the prospect in How to Find ET with Infrared Light, an article appearing in the June, 2013 issue of Astronomy. Jeff Kuhn (University of Hawaii), Svetlana V. Berdyugina (University of Freiburg), David Halliday (Dynamic Structures, Ltd., in British Columbia), and Caisey Harlingten (Searchlight Observatory Network, Norwich, England) believe that a survey out to 60 light years using their methods could make a definitive call on the existence of any civilizations there. The attempt revolves around the use of power.

Consider that Earth’s current terrestrial power production is 15 terawatts, which turns out to be 0.04 percent of the total solar power received on Earth from the Sun. The authors designate the ratio of a civilization’s power production to the amount of solar power it receives as Ω. The article points out that the total power used by photosynthesis on Earth is 0.2 percent of the total light falling on the planet from the Sun — it’s interesting to see that our civilization consumes only 20 percent as much power as the biology that supports us. But let’s carry this forward:

As Earth-like civilizations evolve, they use more power. For example, in Roman times, we estimate Ω was about 1/1000 what it is today. Humans’ global power consumption is growing by about 2.5 percent per year, even though the world’s population is growing at less than half this rate. In contrast, our knowledge base (the combined total of all recorded information) doubles in just two years. As cultures advance, their information content also must grow, and the power required to manipulate this knowledge eventually dominates a civilization’s total power use.

Finding a civilization through its waste heat radiation thus appears possible, given the right equipment, and what equipment it is. Right now the three largest infrared telescopes being planned are the Giant Magellan Telescope, the Thirty Meter Telescope and the European Extremely Large Telescope. But Kuhn and his colleagues need to go bigger. They’re talking about an instrument with a primary mirror of 77 meters, fittingly called Colossus.

Image: The Colossus Telescope, a high-resolution, multiple-mirror giant instrument, will have the ability to directly image the heat generated by other civilizations on planets orbiting stars near us in the Milky Way. Credit: Innovative Optics/Colossus Corporation.

A huge collecting area and an adaptive optics system to correct for the effects of Earth’s atmosphere are essential, as are techniques of ‘thin-mirror slumping’ and polishing technologies being developed by the team through their company Innovative Optics, which operates its research and development out of the University of Hawaii’s Institute for Astronomy in Maui as well as at the National University of Mexico in Ensenada. I pulled this from the Innovative Optics website in a section describing the team’s methodology:

Our proprietary processes drastically reduce the time and cost of production of precision optics. Our optics are produced by fire polishing flat glass (which avoids time-consuming abrasion techniques and leaves a smoother, optically-superior mirror surface), then “slumping” the hot glass under controlled conditions to the desired final shape; no grinding or rough polishing step is required.

The site goes on to describe what it calls ‘Live Mirror’ technologies that provide the adaptive optics needed to eliminate atmospheric distortion. Innovative Optics claims its mirrors can be very thin (2.5 cm thick for an 8-meter diameter Live Mirror) and therefore lightweight, at roughly 70 kg per square meter of surface area, a significant reduction over conventional mirrors. Colossus is envisioned as comprising approximately sixty of these 8-meter mirror segments, with a field of view that would take in only a few arcseconds of the sky at any time, allowing the designers to optimize for star-like sources even as the design holds down costs.

Using a sensitive coronagraph to remove scattered light that would obscure an exoplanet, Colossus would be able to find hundreds of Earth-sized or larger planets in the habitable zone including any civilizations on their surfaces. Innovative Optics is working with Dynamic Structures (Vancouver, BC) on design and construction issues, although issues of funding and location remain to be resolved. Backed by ‘a group of physicists, engineers, telescope builders, philanthropists, and businessmen,’ the team believes the technology exists to make Colossus a reality. “The Colossus would give us insight into whether civilization is a fragile development or if it is common,” the article concludes. “And we’d learn this without announcing ourselves.”

“Humans’ global power consumption is growing by about 2.5 percent per year, even though the world’s population is growing at less than half this rate.”

A global per capita measure is misleading. The growth in developing economies is greater than the average and in developed economies is lower and even negative in some cases. All that’s currently happening is a great “leveling” as global disparities are lessened.

“In contrast, our knowledge base (the combined total of all recorded information) doubles in just two years. As cultures advance, their information content also must grow, and the power required to manipulate this knowledge eventually dominates a civilization’s total power use.”

Again, this can be misleading. The energy to store, retrieve and manipulate each bit is falling. While it’s early to be certain I anticipate that the cost decline will eventually overcome the data increase rate.

Extrapolation is dangerous when it is rife with assumptions about technology and society, where the pace and type of change is not so predictable.

Excellent piece, Paul, and exciting to know that those massive telescopes could actually find ETI civilizations even if they are not trying to get our attention, which seems to be the case at least for the last fifty-plus years.

I hope those who do run these SETI programs with those instruments also get beyond the idea that advanced civilizations will remain on a planet leaking lots of heat and aim them at places that Dyson Shells and Matroishka/Jupiter Brains might dwell, such as in the colder outer regions of the Milky Way. They will generate lots of heat that will be visible in the infrared.

We should also look for infrared signals in comet and planetoid belts and around black holes (collapsars), where advanced societies would take advantage of the fact that dumping their waste into the collapsar would return more energy than it received.

By the way, the authors had originally considered directed gamma rays as the method ETI might use for interstellar communications, before going with radio waves.

Since we now know that the galaxy is not exactly bursting with alien chatter, at least in the radio bands in our vicinity, looking at viable alternatives for species we can only guess about at present is the sensible way to go. Keep radio, of course, as it has its merits, but expand the parameters.

SETI, the search for extraterrestrial intelligence, has seen astronomers scouring the sky for decades in hopes of receiving artificially generated radio signals sent by alien civilizations. But then, there’s a good chance we’ve already found just such a signal. And 1977 saw the most tantalizing glimpse ever.

Nicknamed the “Wow!” signal, this was a brief burst of radio waves detected by astronomer Jerry Ehman who was working on a SETI project at the Big Ear radio telescope, Ohio. The signal was, in fact, so remarkable that Ehman circled it on the computer printout, writing “Wow!” in the margin — and unintentionally giving the received radio signal the name under which it would become famous.

Despite a lot of effort, no identification has been found for the signal’s source, and no repeat signal has ever been found. It’s a complete mystery. The only conclusion that can be drawn is if the signal truly did originate in deep space, then it was either an astrophysical phenomenon of which we’ve never seen before, or it truly was an intercepted alien signal.

To explain scientific observations, the normal method is to construct hypotheses and then test them. If your hypothesis is incorrect, it will fail to explain the observation. You can then continue this way, using different hypotheses, until you find something which can accurately describe what you’ve observed (if you ever watch Mythbusters, you may be familiar with how this works).

But with the Wow! signal, researchers ran into difficulty. After trying and failing to find any repeat of the signal, Ehman was skeptical of its origin, stating that “something suggests it was an Earth-sourced signal that simply got reflected off a piece of space debris.” But when he tried to investigate that explanation, he only found more problems.

Presents essays exploring the societal, anthropological, and religious dimensions of astrobiology and SETI

Offers a comprehensive overview of the extraterrestrial life debate from antiquity to the present day

Demonstrates possible impacts of the discovery of extraterrestrial life on human society

Explores the importance of analogies for contemporary astrobiologists, who search for life beyond Earth based on terrestrial life and environments
Provides insights into the nature of scientific discovery through in-depth case studies

This book addresses important current and historical topics in astrobiology and the search for life beyond Earth, including the search for extraterrestrial intelligence (SETI).

The first section covers the plurality of worlds debate from antiquity through the nineteenth century, while section two covers the extraterrestrial life debate from the twentieth century to the present. The final section examines the societal impact of discovering life beyond Earth, including both cultural and religious dimensions.

Throughout the book, authors draw links between their own chapters and those of other contributors, emphasizing the interconnections between the various strands of the history and societal impact of the search for extraterrestrial life.

The chapters are all written by internationally recognized experts and are carefully edited by Douglas Vakoch, professor of clinical psychology at the California Institute of Integral Studies and Director of Interstellar Message Composition at the SETI Institute.

This interdisciplinary book will benefit everybody trying to understand the meaning of astrobiology and SETI for our human society.

Table of contents Part I. The Early Extraterrestrial Life Debate.- Chapter 1. The Extraterrestrial Life Debate from Antiquity to 1900.- Chapter 2. Early Modern ET, Reflexive Telescopics, and Their Relevance Today.- Chapter 3. Extraterrestrial Life as the Great Analogy, Two Centuries Ago and in Modern Astrobiology.- Chapter 4. Hegel, Analogy, and Extraterrestrial Life.- Chapter 5. The Relationship Between the Origins of Life on Earth and the Possibility of Life on Other Planets: A Nineteenth-century Perspective.- Chapter 6. Pioneering Concepts of Planetary Habitability.- Part II. The Modern Extraterrestrial Life Debate.- Chapter 7. The Twentieth Century History of the Extraterrestrial Life Debate: Major Themes and Lessons Learned.- Chapter 8. The Creator of Astrobotany, Gavriil Adrianovich Tikhov.- Chapter 9. Life Beyond Earth and the Evolutionary Synthesis.- Chapter 10. The First Thousand Exoplanets: Two Decades of Excitement and Discovery.- Chapter 11. Extraterrestrial Life in the Microbial Age.- Part III. Societal Impact of Discovering Extraterrestrial Life.- Chapter 12. The Societal Impact of Extraterrestrial Life: The Relevance of History and the Social Sciences.- Chapter 13. Cultural Resources and Cognitive Frames: Keys to an Anthropological Approach to Prediction.- Chapter 14. The Detection of Extraterrestrial Life: Are We Ready?.- Chapter 15. Impact of Extraterrestrial Life Discovery for Third World Societies: Anthropological and Public Health Considerations.- Chapter 16. Impossible Predictions of the Unprecedented: Analogy, History, and the Work of Prognostication.- Chapter 17. Mainstream Media and Social Media Reactions to the Discovery of Extraterrestrial Life.- Chapter 18. Christianity’s Response to the Discovery of Extraterrestrial Intelligent Life: Insights from Science and Religion and the Sociology of Religion.- Chapter 19. Would the Discovery of ETI Provoke a Religious Crisis?.- Index.

The book price, however, will keep the general public from acquiring it easily or at all. $139 just for the electronic version??

“Still, according to SDE, the average distance we should expect to find any alien intelligent life form may be 2,670 light-years from Earth. There is a 75% chance we could find ET between 1,361 and 3,979 light-years away.
500 light-years away, the chance of detecting any signal from an advanced civilization approaches zero. And that is exactly the range in which our present technology is searching for extraterrestrial radio signals. So, the “Great Silence” detected by our radio telescopes is not discouraging at all. Our signals just need to travel a little farther – at least 900 light years more – before they have a high chance of coming across an advanced alien civilization.”

Can someone explain the discrepancy in the statements and figures? Are the basis of hypotheses so different?

So far noone has produced better than Drake its equation. Statistical regression is a well established method and statistical field. By combining two we still get valid result and assurance are we or are we not withing the error margins.

AFAIK up to 500 ly is SETI’s current technical capability.

If the professional claim the results within 60 ly will resolve the question definitely then I either I don’t understand or someone is overoptimistic.

I foresee that around 60 ly the result will be negative. Which is fine as we know if they are then they are pretty far away but not definitely non existing.

I have been wondering for over a decade how SETI could
detect a carrier signal, now this comes along to find possible
civilizations thus making it possible to detect carrier signals
similar to what we Terran’s use.

We may be able at some point to pick up an Alien signal, but will we understand it. I personally think technologically intellegent life is very,very rare at around one or two per Gallaxy at most, there are just to many factors that can act against its emergence.

“Colossus” is certainly worth building if (as the authors say) it could be used to study extra-solar planets, stellar surfaces, black holes, and quasars. I suspect those would be its primary missions, with SETI as a distant second. Given our current understanding (ET civilizations probably rare to non-existent) it’s unlikely such an instrument would be built for SETI alone.

“Can someone explain the discrepancy in the statements and figures? Are the basis of hypotheses so different?”
Yes, there are different calculations IIRC the one you quoted uses Monte Carlo simulation.

The basic point is that the traditional SETI method is quite obvious(to anyone studying it) to fail and relies on quite fantastic assumptions(civilizations sending radio signals to Earth with gigantic power for millions of years). The best we can do right now is to search for exo-planets and biospheres(using technology that we already have on door step) and for signs of technological activity like Dyson Spheres(although even that is very far possibility).

I’m always in favour of building more capable telescopes. Finding the funding is the problem. Well then I’d like to publicly announce that if I win the Powerball I’ll build the Colossus providing another more compelling astronomical project doesn’t seduce me. Would $800 million cover it? Nope.
Will still require matching grants and/or donations.

If Colossus is able to closely examine almost all nearby stars (no Earth bound telescope can view the entire sky, even at the equator there is too much atmospheric extinction to observe the celestial polar regions properly) it would help to compensate for the loss of SIM and the TPF.

If this telescope is capable of detecting bio-markers and other molecules in the spectrum from HZ planets of nearby stars that in itself is reason to build it. What other capabilities it has are pure gravy. While doing its primary observations who can say what else it might stumble upon?

I agree with Mike. The more windows on the universe the more we learn. “Look for what is detectable”.

My heart aches everytime I watch the ISS go over. I love the idea, utility and the sheer dazzle of it. But at what price? How many telescopes, probes…how much have we sacrificed to have a guy playing Bowie and demonstrating micro g parlour tricks?

End-to-end interstellar communication system design for power efficiency

David G. Messerschmitt

(Submitted on 21 May 2013)

Interstellar radio communication accounting for known impairments due to radio propagation in the interstellar medium (attenuation, noise, dispersion, and scattering) and motion is studied. Large propagation losses and large transmitted powers motivate us to maximize the power efficiency, defined as the ratio of information rate to average signal power. The fundamental limit on power efficiency is determined.

The power efficiency for narrow-bandwidth signals assumed in many current SETI searches has a penalty in power efficiency of four to five orders of magnitude. A set of five power-efficient design principles can asymptotically approach the fundamental limit, and in practice increase the power efficiency by three to four orders of magnitude. The most fundamental is to trade higher bandwidth for lower average power. In addition to improving the power efficiency, average power can be reduced by lowering the information rate. The resulting low-power signals have characteristics diametrically opposite to those currently sought, with wide bandwidth relative to the information rate and sparse distribution of energy in both time and frequency. The design of information-free beacons power-optimized for a given observation time is also undertaken. Such beacons need not have wide bandwidth, but at low powers their energy is sparsely distributed in time.

The discovery of both beacons and information-bearing signals is analyzed, and shown to require a substantial number of observations (growing as power is reduced) to achieve a high probability of success. The “false alarms” in current searches are characteristic signatures of possible power-efficient and power-optimized signals. Although existing SETI searches will fail to discover these signals, they can be discovered using common algorithms with straightforward modification to current search methodologies.

I will not to doubt the possibility of existence of Dyson’s spheres or another planetary constructions in space, but if a civilization is so advanced that can build such colossally constructions,
is needed this construction for the extraction of a star energy? Maybe an advanced civilization can generate the energy using more place saved sources (like vacuum energy etc.)? To live on the surface of the Dyson’s sphere needs artificial gravity, if this civilization is still biological.

“My heart aches everytime I watch the ISS go over. I love the idea, utility and the sheer dazzle of it. But at what price? How many telescopes, probes…how much have we sacrificed to have a guy playing Bowie and demonstrating micro g parlour tricks?”

Nothing. Absolutely nothing is lost. Right the opposite – the gain the ISS bring on a broad range of knowledge and science is not measurable. If the only concern is a Canadian doing micro-gravity magic tricks then you have clearly missed the understanding what is life for. There is no fun w/o fun.

If you are so concerned about your tax dollar, send the the bill, I’ll foot it.

Rather than waste heat radiation, wouldn’t it help to first detect methane and oxygen in exoplanet atmospheres to narrow down the candidate planets that might harbor intelligent life? Our ability to do that is just around the corner compared to how long it would take to plan and construct a 77 meters primary mirror telescope, not to mention its equally massive price tag. Knowing which planets (and how many) have tell-tale concentrations of respiratory gases would let us know whether it’s worth our time and effort to even consider searching for waste heat. If planets with methane/oxygen are exceedingly rare and far, far away, then a telescope like Colossus wouldn’t be successful in finding signs of exo-industrial activities, although it could serve many other purposes as already mentioned.

I am a bit puzzled. I thought I had understood that detecting and spectro-analyzing biosignatures, heavily depending on the infrared, are not possible from the earth surfacem regardless of magnifying power, resolution or even adaptive optics, because the earth atmosphere absorbs too much of the infrared. That even the E-ELT would not be sufficient, because of this reason. And hence, for spectro-analyzing biosignatures a space-based platform will always be necessary.
Can anyone say something anything conclusive about this?

NASA has completed a study about the potential use of a telescope donated by the NRO to carry out an astronomy mission called WFIRST. Philip Horzempa examines how this proposed mission would also be very useful in search for and studying extrasolar planets.

Detecting non-equilibrium gases (O2 and Methane) or any other biomarker is another primary task for Colossus. Since it will spatially resolve the planet from the star while suppressing the starlight by many orders of magnitude it also becomes the most powerful instrument for detecting life (in general) on exoplanets…

While I welcome the concept of building a vast telescope to measure infrared outputs from possible civilisations, I can’t help but feel that it is both a waste of time and resources, especially as the economic crisis is still in full swing and there is no visible solution for ending it.

On the other hand, I think it’s important for people to see the evidence that we are not the only technologically-advanced species within 60 ly of Earth.

But as someone pointed out above, the likelihood of there being any technological civilisations within that radius is extremely low, so the cost/benefit analysis is definitely weighted against the usefulness of such a telescope.

I have rather reached the conclusion that it would be better for a telescope to be built that could actually see Earth-like planets in orbit around other stars and analyse their atmospheres – both for the purpose of cataloguing eventual new sites for colonisation in the future, and for defining which planets in general are habitable for any living organism, whether intelligent or not.

But that is a long way in the future. Surely it would be better for considerably cheaper probes to be sent to the moons of Jupiter and Saturn so that we can seek life within our own solar system, before we try to find evidence of it at such vast distances in the Milky Way.

I think the discovery of another biogenesis within our own solar system would have a deeply profound impact both on our civilisation as a whole. and also on the religious beliefs of people here, leading up gradually to the more definite prospect that the entire universe is teeming with life. Imagine, if you will, the shock that so many people will experience if technological life is discovered elsewhere in the galaxy. If they are not prepared for it, for example, by having been shown evidence of primitive life beneath the ice crust of Europa or swimming in the lakes of Titan, then the resultant hysteria may rock many societies to their foundations.

“While I welcome the concept of building a vast telescope to measure infrared outputs from possible civilisations, I can’t help but feel that it is both a waste of time and resources, especially as the economic crisis is still in full swing and there is no visible solution for ending it.”

We just had a war that cost several trillion dollars, with the result that Iraq has a barely stable government and over one thousand citizens and soldiers were killed in sectarian violence in the month of May alone. If things collapse and things go back to the way they were (dictators, theocracy), it would not be surprising given the long history of the region.

Americans spend over $3 million annually on chewing gum. I have yet to hear anyone say due to the economic crisis that gum should be banned. I can go on easily, but I hope the point is made.

During the height of the Great Depression in the 1930s, which makes our current situation look like just an off day or two, the 200-inch, 17-ton mirror for the Hale Telescope that would eventually find its way to Mount Palomar was made and shipped across the United States by railroad. Everywhere it stopped crowds came to see it, or at least its huge labeled container. In several places where the public could not get a good look, riots ensued.

While the mirror was slowly being made at Corning Glass in New York, people paid money for tickets to watch the technicians work on the Giant Eye, as it was nicknamed.

The residents of that era knew they were getting a glimpse of a better future that was not too far away, one they could fix and build themselves. See here for more information:

It would be nice if more people had that attitude today. Perhaps it would end our economic situation sooner and we could get on to doing truly great things that matter. Like figuring out the true nature of the Universe.

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In Centauri Dreams, Paul Gilster looks at peer-reviewed research on deep space exploration, with an eye toward interstellar possibilities. For the last nine years, this site has coordinated its efforts with the Tau Zero Foundation, and now serves as the Foundation's news forum. In the logo above, the leftmost star is Alpha Centauri, a triple system closer than any other star, and a primary target for early interstellar probes. To its right is Beta Centauri (not a part of the Alpha Centauri system), with Beta, Gamma, Delta and Epsilon Crucis, stars in the Southern Cross, visible at the far right (image: Marco Lorenzi).

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